IRC RULE MEASUREMENTS OF SAILING BOATS

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IRC RULEMEASUREMENTS OF SAILING BOATS

• For Turkish Offshore Racing Club
• And
• Turkish Sailing Community

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• PLAN
• Introduction IRC PRINCIPLES
• Part 1 HULL MEASUREMENTS
• Part 2 RIG AND SAILS MEASUREMENTS

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• IRC PRINCIPLES
• IRC Self declared measurements
• Assistance of an IRC Appointed Measurer
• IRC Appointed Measurer required for
• IRC WEIGHING and ENDORSED CERTIFICATES

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OFFICIAL DOCUMENTATION

• IRC Rule IRC Notices
• www.uncl.com and UNCL IRC Yearbook
• www.tayk.org
• www.rorcrating.com and RORC IRC Yearbook
• ISAF Equipment Rules of Sailing
• www.isaf.org

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MEASUREMENT EQUIPMENT

• The owner or measurer shall use measuring
  instruments with a degree of precision and
  accuracy that matches the measurements being
  taken.
• - Metal tape measurers and rulers
• (various lengths depending on the measurement),
• - Spirit levels,
• - Plumb lines,
• - Floating wooden tape rulers,
• - Adhesive tape, cords, note book, pencils,
• permanent marker, screwdriver

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BASIC PRINCIPLES

• NO TOLERANCES ON IRC MEASUREMENTS
• IRC Rule 19.8 deals with RATING REVIEW, the
  tolerances are applied in the case of a control
  by a measurer.
• Declaring the measurement, the owner shall
  declare the measured ones he shall not
  artificially diminish the measurements using IRC
  Rule 19.8.

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BASIC PRINCIPLES

• A MEASUREMENT SHALL BE ACCEPTED AT A TIME T.
• Measurements may slightly vary for environmental
  or meteorological reasons (moisture,
  temperature).
• DATE AND SIGN ALL YOUR MEASUREMENTS
• IRC uses the MKSA1 Metric system (See IRC Rule
  12)
• Sails measurements in metres to two decimal
  places.
• Other linear measurements in metres to three
  decimal places.
• Weights expressed in Kg
• Boats weights rounded to the nearest 10
  kilograms.
• 1 MKSA  Metre, Kilogram, Second, Ampere

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EXISITING MEASUREMENTS

• Other measured rating systems (IOR, IMS ORC Club
  and PHRF).
• Part of those measurements can be used provided
  that the boat to be measured matches the
  certificate of measurement presented in order to
  make sure that the owner has not made any
  changes.
• As a general rule, overall hull length, max beam,
  draft, are reliable form one certificate to
  another. Changes made to any of those parameters
  are visible.
• Other measurements, such as weight, overhangs
  and sails measurements should be carefully
  treated if coming from another certificate.

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IN CASE OF DOUBT

• Always refer to Official Documentation
• Refer to other IRC Measurers
• Refer to the UNCL IRC Rating Office VIA TAYK.

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PART ONEHULL MEASUREMENTS
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MEASUREMENTS ON LAND

• For accurate measurements, the boat in a
  horizontal plan. For that, use a spirit level.
  The operation may be difficult.
• Those measurements (Bmax, Draft, LOA) are not
  necessary for production boats with no
  modifications.
• (in such a case, inform the IRC Rating Office
  about the series name and the draft).
• Those measurements are required only for One
  off and the first of a mass production boat.
• Those measurements may be required for Endorsed
  certificates.

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LOA, HULL LENGTH

• LOA The length overall of the hull excluding
  bowsprit and other rigging if any, stem fittings,
  stern fittings, pulpits, any overhanging rudder
  and rudder hangings.
• When the boat ashore on a horizontal plan, place
  a plumb line at the forward, another at the aft.
  Measure between each plumb lines and an
  intermediate fixed reference point.
• LOA AB

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BMax, MAXIMUM BEAM

• Beam the maximum horizontal dimension of the
  boat in any transverse section, excluding any
  rubbing strake or toe rail.
• Inspect for maximum beam station sighting from
  off the boat. Do it from both ahead and stern of
  the boat. It is easy to be fooled by the shape of
  the boat. Maximum beam is nearly always further
  aft than you think. If in doubt, check several
  stations to find a maximum value.
• Using a level held vertically at the point of
  maximum beam, measure inboard to a convenient
  point on the deck of the boat. Repeat from the
  other side.

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DRAFT

• Draft The maximum depth of the boat or any of
  its appendages below the water plane, in the
  condition of Empty Weight (see Rule 22.0).
• In the case of any movable appendage, which is
  not fixed down while racing, the minimum depth is
  also required (keel fully up and fully down).
• Draft is measured in 2 steps ashore and afloat.

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DRAFT- Ashore

• Establish a convenient reference point on each
  side of the boat above the waterline in way of
  the section at maximum keel depth.
• Using a spirit level, project horizontally from
  the underside of the keel outboard to vertically
  below the reference point each side. Measure
  vertically down from each reference point.

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DRAFT- Afloat

• Everybody shall be off the boat when measuring
  and the boat shall be empty (IRC 22).
• Measure vertically downwards form the reference
  point each side to the water surface.
• By subtraction from the ashore figures, and then
  averaging the result, draft is found.

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MEASUREMENTS AT SEA

• Each measurement afloat is done with the boat in
  EMPTY TRIM (IRC Rule 22).
• NO WIND
• AND
• FLAT WATER PLANE
• REQUIERED

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OVERHANGS BO, SO, y, x, h

• IRC Rule definitions
• BO The horizontal distance from the forward point
  of LWP to the forward limit of LOA, in the
  condition of Empty Weight (see Rule 22.0).
• SO The horizontal distance from the aft point of
  LWP to the aft limit of LOA, in the condition of
  Empty Weight (see Rule 22.0).
• Using a pair of plumb lines attached to the
  extreme ends of the hull (excluding fittings) at
  bow and stern use a floating wooden rule to
  measure the overhangs at bow (BO) and stern (SO).

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• y The vertical distance from the water plane to
  the lowest point on the transom, in the condition
  of Empty Weight (see Rule 22.0).
• Using the plumb line at stern, measure along the
  line the distance from the end of hull to the
  water plane. Only one EXCEPTION reversed
  transoms

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Scow Bow or knuckle exposed

• x The horizontal distance from the forward point
  of LWP to the lowest point on the stem at a
  tangent of 450 to the horizontal, in the
  condition of Empty Weight (see Rule 22.0).
• h The vertical distance from the water plane to
  the lowest point on the stem at a tangent of 45
  to the horizontal, in the condition of Empty
  Weight (see Rule 22.0).

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Scow Bow or knuckle exposed

• Using a Spirit Level 45 inclined, mark the
  relevant point on the knuckle.
• Best method is to mark the point when the boat
  is ashore, and to measure when afloat.

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IRC WEIGHT - WEIGHT CERTIFICATE

• Weighting device shall be done by an appointed
  IRC measurer.
• IRC Measurer shall be able to proof to the owner
  and to the Rating Office that the load cell he
  uses is well calibrated (it shall be calibrated
  at least once a year).
• NEVER USE DATAS PROVIDED BY A TRAVEL LIFT,
  NEITHER CRANES LOADCELLS.
• When a boat weighed, overhangs measurements shall
  be provided to IRC Rating Office.
• Several items shall be removed, others shall stay
  aboard. Rule 22 explains how to prepare a boat
  properly before weighing.
• Never weight with more than 10 knots of wind.
• A weight certificate shall be provided to the
  owner. Each parts shall be filled and the
  document shall be signed both by the owner (or
  his representative) and the official measurer. If
  not, this document will not be accepted as valid
  by the IRC Rating Office.

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Weight certificate Checklist

• Part A Tanks note gasoline and water into the
  boats tanks.
• Part B Internal Ballast note any internal
  ballast weight, their position, and the type of
  fixation.
• Part C Accommodations for each item, note
  Aboard or Removed with the number of removed
  items, or No Object if the series boat is not
  fitted with an equipment (for instance, no table
  in a Melges 24 No object). Note the number and
  type of batteries.
• Part D Movable chest or Cockpit boxes ( J 109,
  First 36.7, First 40.7, IMX 40, IMX 45)
• Part E Other accommodations take note of
  specifics and anything that appears to be
  unusual.
• IRC Rating Office shall be informed if the yachts
  are weighed with or without those various
  equipments, as the IRC weighted boat shall race
  in the same configuration.
• Part F Mast and rig note the most details you
  can mast and rig material, Checsktays, runners
• Deduction
• Tare remove from the gross weight all the
  fittings necessary to weight (straps)
• Gasoline remove from the gross weight the
  quantity of gasoline aboard when weighting
  multiplied by 0.9.
• Water remove from the gross weight the
  quantity of water aboard when weighting.
• Others all items not removed before weighting
  in spite of they should be.
• Note the measured overhangs, date and place.
  Measurer and owner shall sign the document.
• Any incomplete IRC Weight Certificate will be
  refused by IRC Rating Office.

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PART TWORIG AND SAILS MEASURMENTS
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• P The hoist of the mainsail measured on the mast,
  from the top of the boom when set at right angles
  to the mast or the corresponding top of a
  permanent 25 mm band of contrasting colour, and
  the bottom of a similar 25 mm band at the top of
  the mast above which the mainsail shall not be
  hoisted.
• If there is no top band the measurement shall be
  taken to the top bearing surface of the halyard
  shackle.
• P is never measured directly from the sail

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• E The foot of the mainsail measured along the top
  of the boom set on the centre line and at right
  angles to the mast, from the back of the mast to
  the inside of a permanent 25 mm band of
  contrasting colour beyond which the mainsail clew
  point shall not be set.
• If there is no band the measurement shall be
  taken to the aft end of the boom.
• E is never measured directly from the sail.

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• J The base of the fore triangle measured as the
  horizontal distance from the front of the mast at
  deck level to the point where the forestay meets
  the deck, projected if necessary.
• The point where the forestay meets the deck may
  depend on your rig type.

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• FL The forestay length measured from where the
  forestay meets the deck, or from the jib outhaul
  in the case of a bowsprit, to the forestay
  attachment point on the front of the mast or to
  where the forestay intersects the front of the
  mast, projected if necessary.

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• STL or (SPL) The length of the longest spinnaker
  pole, whisker pole or bowsprit measured on or
  near the centre line of the boat
• from the forward face of the mast tube to the
  extremity of the spinnaker pole, whisker pole or
  bowsprit,
• or the horizontal length from the forward face
  of the mast tube at deck level to the spinnaker
  tack point on deck projected vertically as
  necessary, whichever is the greatest.

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SAILS

• BASIC PRINCIPLES
• For each sail measurement
• sails shall be on the floor
• and have just sufficient tension applied to
  remove wrinkles across the line of
• the measurement being taken.

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Mainsail MHW, MTW, MUW

• MHW The half width of the mainsail, measured as
  the shortest distance between the half leech
  point and the luff, bridging any hollows in the
  leech of the sail.
• MTW The three quarter width of the mainsail,
  measured as the shortest distance between the
  three quarter leech point and the luff, bridging
  any hollows in the leech of the sail.
• MUW The seven eighth width of the mainsail,
  measured as the shortest distance between the
  seven eighth leech point and the luff, bridging
  any hollows in the leech of the sail.
• ONLY MHW, MTW and MUW are measured directly on
  the mainsail

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• First, look for the MUW measurement point on the
  leech, folding the sail (head point on clew
  point). Mark it on the leech.
• Second, look for the MTW measurement point,
  folding the sail (head point on the MHW
  measurement point).
• Third, look for the MUW measurement point,
  folding the sail (hear point on the MTW
  measurement point).

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• On the biggest genoa, the one with the biggest
  Headsail Area (HSA), you have to measure LL, LP
  and HHW (use the same method as for MHW).
• LLmax biggest Luff Length of all the headsails
  aboard.
• Measurements shall be taken using the relevant
  Clew, Tack or Leech points.

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HEADSAIL TOP WIDTH

• HHB The widest headsail top width of any
  headsail carried measured as the distance between
  the head point and the aft head point.

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Spinnaker SLU, SLE, SF, SHW

• SF The foot length of the largest area spinnaker
  carried, measured between the clew points
• SHW The half width of the largest area spinnaker
  carried, measured between the half leech points.
• SLE The leech length of the largest area
  spinnaker carried, measured from the clew point
  to the head point.
• SLU The luff length of the largest area spinnaker
  carried measured from the tack point to the head
  point.

• Same method for symetrical and asymetrical
  spinnakers. Only the largest spinnaker is
  declared.

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RIG FEATURES

• Mast material, rod rigging or not, number of
  pairs of spreaders and sweptback angle, jumpers,
  runners, checkstays, shall be noted on the
  petition. All unusual features shall be declared
  to IRC Rating Office (See IRC Rule26.2.2),
  textile rigging, radar on mast
• Consistently, applications for IRC certificates
  are received with erroneous information relating
  to backstays, runners and checkstays. IRC Rule
  added the following definition in 2007
• Backstay An item of running rigging from the
  masthead to the stern of the boat which may be
  adjusted while racing.
• Runner An item of running rigging from the
  mast below the masthead in the vicinity of the
  forestay to the stern of the boat which may be
  adjusted while racing.
• Checkstay An item of running rigging from the
  mast significantly below the forestay to the
  stern of the boat which may be adjusted while
  racing.